1.Field of the Invention
The present invention relates to data communications, and more particularly, to a device for data communications between a Wireless Application Protocol (WAP) terminal and a WAP server, and a method thereof.
2. Description of the Related Art
In general, a WAP server is connected between an Internet server which provides various information and a WAP terminal capable of receiving the information provided from the Internet server, to convert different data formats and different protocols between the Internet server and the WAP terminal. Also, the WAP server can provide the WAP terminal with its own information.
FIG. 1 is a block diagram of a conventional data communications device between a WAP terminal and a WAP server.
The data communications device of FIG. 1 comprises a WAP terminal 10, an interworking function (IWF) unit 12, a public switched telephone network (PSTN) 13, an Internet service provider (ISP) 14 and a WAP server 16.
The IWF unit 12 performs routing functions between the WAP terminal 10 and the ISP 14. The ISP 14 is one of companies providing general communication service such as HITEL or UNITEL. The WAP server 16 provides the WAP terminal 10 with its own information and much information from an Internet server (not shown).
FIG. 2 shows a protocol stack of each block of the data communications device shown in FIG. 1.
A protocol stack of the WAP terminal 10 consists of a plurality of protocol layers including a Circuit Switch Data services protocol (CSD(IS-707)), a Peer-to-Peer Protocol (PPP), an Internet Protocol (IP), a Wireless Transaction Protocol (WTP) and User Data Program Protocol (UDP), a Wireless Session Protocol (WSP) and a Wireless Application Environment protocol (WAE). Also, the CSD(IS-707) includes an IS-95 protocol, a Radio Link Protocol (RLP), a PPP, an IP and a TCP. The protocol layers are well known to those skilled in the art, so explanation thereof will be omitted.
FIG. 4 is a diagram illustrating data flow in the data communications device shown in FIG. 1.
The operation of the data communications device of FIG. 1 will be described with reference to FIG. 4.
It is assumed that the WAP terminal 10 intends to receive Internet or electronic mail (E-mail) services. Here, the WAP terminal 10 is ready to-receive a common call or data (Internet or E-mail) in a normal state. When a user of the WAP terminal 10 connects the WAP terminal 10 through the IWF unit 12 and the PSTN 13 to the ISP 14 using a telephone number for connection with the Internet, the ISP 14 connected to the WAP terminal 10 allows the user to receive the Internet or E-mail services. Also, when the user wants to stop receiving the Internet services, the ISP 14 disconnects the call from the WAP terminal 10, returning to the ready state.
In detail, the WAP terminal 10 sends an Origination Message requesting connection of its call to the IWF unit 12. The IWF unit 12 receives the Origination Message from the WAP terminal 10, and then sends an Origination Ack message acknowledging reception to the WAP terminal 10. The IWF unit 12 sends a Connect Request message for connection of a modem to the ISP 14. The ISP 14 receives the Connect Request message and sends a Connect  less than rate greater than  message indicating the connection of the modem through the PSTN 13 and the IWF unit 12 to the WAP terminal 10. Under conditions that the WAP terminal 10 and the IWF unit 12 are connected to each other, the WAP terminal 10 sends WAP data (Internet or E-mail services request data) which the user Wants to receive through the IWF 12 and the ISP 14, to the WAP server 16. After the WAP server 16 receives the WAP data, the WAP server 16 sends WAP server data which is retained in the WAP server itself, or data taken from an Internet server (not shown) through the ISP 14, the PSTN 13 and the IWP 12 to the WAP terminal 10.
The data communications device of FIG. 1, having the protocol stack as shown in FIG. 2, has the following problems.
First, because the CSD(IS-707) in the protocol stack of the WAP terminal 10 includes the IPIPPP as shown in FIG. 3, the protocol stack of the WAP terminal 10 has IP/PPP protocol layers in duplicate. As a result, there is much overhead during transmission of data, so that transmission efficiency becomes low. That is, the resources of the terminal are not efficiently used. Also, when a user intends to connect to the WAP server 16 or the Internet, connection with the ISP 14 is achieved through the PSTN 14. Thus, the connection rate becomes slow, and using the PSTN and the ISP 14 may be subject to charges by the telephone company or the ISP. Also, the transmission of data is inefficient because it requires multiple steps as shown in FIG. 4.
To solve the above problems, it is a first object of the present invention to provide a device for data communications between a Wireless Application Protocol (WAP) protocol and a WAP server, adopting a protocol stack in which a single Internet Protocol/Peer-to-Peer Protocol (IP/PPP) layer included in a Circuit Switch Data services (ISD) protocol of the WAP terminal is used and an interworking function (IWF) unit also acts as an Internet service provider (ISP).
It is a second object of the present invention to provide a communication method of the data communications device for the first object.
It is a third object of the present invention to provide a device for data communications between a WAP terminal and WAP server, which performs data communications while performing switching between the WAP terminal and a non-WAP terminal.
It is a fourth object of the present invention to provide a communication method of the data communications device for the third object.
Accordingly, to achieve the above first object, there is provided a device for data communications between a Wireless Application Protocol (WAP) terminal and a WAP server, comprising: a plurality of WAP terminals each having a protocol stack in which a Circuit Switch Data service (CSD) protocol layer is laid under a Wireless Transaction Protocol (WTP) layer and a Wireless Datagram Protocol (WDP) layer, for generating WAP data which is service request data; a plurality of WAP servers each having a protocol stack in which a Transmission Control Protocol (TCP) layer and an Internet Protocol (IP) layer are laid under a WTP layer and a WDP layer, for providing the WAP terminals with WAP server data according to the WAP data; and an interworking function (IWF) unit having a CSD protocol layer connected to the CSD protocol layers of each WAP terminal, and a TCP layer and an IP layer which are connected to the TCP and IP layers of each WAP server, for mapping the WAP terminals to the corresponding WAP servers, wherein each WAP terminal communicates with the IWF unit through a single Internet Protocol/Peer-to-Peer Protocol (IP/PPP) layer included in its own CSD protocol layer, and the IWF unit communicates through the Internet with each WAP server.
To achieve the second object, there is provided a communication method of a data communications device including a plurality of WAP terminals having a protocol stack in which a Circuit Switch Data service (CSD) protocol layer is laid under a Wireless Transaction Protocol (WTP) layer and a Wireless Datagram Protocol (WDP) layer, a plurality of WAP servers having a protocol stack in which a Transmission Control Protocol (TCP) layer and an Internet Protocol (IP) layer are laid under a WTP layer and a WDP layer, and an interworking function (IWF) unit having a CSD protocol layer connected to the CSD protocol layers of each WAP terminal, and a TCP layer and an IP layer which are connected to the TCP and IP layers of each WAP server, for communications between each WAP terminal and each WAP server, the method comprising the steps of: (a) transferring an Origination Message for a call connection from each WAP terminal to the IWF unit, and transferring an Origination ACK from the IWF unit to the corresponding WAP terminal in response to the Origination Message; (b) receiving WAP data which is service request data for the WAP servers from the WAP terminals, to map each WAP terminal to the corresponding WAP server in the IWF unit, and transferring the received WAP data through the Internet to the corresponding WAP server; (c) receiving the WAP data to generate WAP server data according to the received WAP data in each WAP server, and transferring the WAP server data through the Internet to the IWF unit; (d) receiving the WAP server data transferred in the step (c) to map the WAP servers to the corresponding WAP terminals in the IWF unit, and transferring the received WAP server data to the corresponding WAP terminals; and (e) communicating in the WAP terminals with the IWF unit through a single Internet Protocol/Peer-to-Peer Protocol (IP/PPP) layer contained in each Circuit Switch Data service (CSD) protocol layer of the WAP terminals.
To achieve the third object, there is provided a device for data communications between a Wireless Application Protocol (WAP) terminal and a WAP server, comprising: a plurality of WAP terminals each having a protocol stack in which a Circuit Switch Data service (CSD) protocol layer is laid under a Wireless Transaction Protocol (WTP) layer and a Wireless Datagram Protocol (WDP) layer, for generating WAP data which is service request data; a non-WAP terminal for generating a common circuit data; a plurality of WAP servers each having a protocol stack in which at least a Transmission Control Protocol (TCP) layer and an Internet Protocol (IP) layer are laid under a WTP layer and a WDP layer, for providing the WAP terminals with WAP server data according to the WAP data; an Internet server for providing the non-WAP terminal with Internet server data according to the common circuit data; an Internet service provider (ISP) having a public switched telephone network (PSTN) circuit layer, for transferring the common circuit data received through a PSTN from the non-WAP terminal, to the Internet server; and an interworking function (IWF) unit having a CSD protocol layer connected to the CSD protocol layers of each WAP terminal, and a TCP layer and an IP layer which are connected to the TCP and IP layers of each WAP server, for performing interfacing between each WAP terminal and each WAP server, and the non-WAP terminal and the ISP, wherein each WAP terminal communicates with the IWF unit through a single Internet Protocol/Peer-to-Peer Protocol (IP/PPP) layer included in its own CSD protocol layer, and the IWF unit communicates through the Internet with each WAP server.
To achieve the fourth object, there is provided a communication method of a data communications device including a plurality of WAP terminals each having a protocol stack in which a Circuit Switch Data service (CSD) protocol layer is laid under a Wireless Transaction Protocol (WTP) layer and a Wireless Datagram Protocol (WDP) layer, a non-WAP terminal for generating a common circuit data, a plurality of WAP servers each having a protocol stack in which at least a Transmission Control Protocol (TCP) layer and an Internet Protocol (IP) layer are laid under a WTP layer and a WDP layer, an Internet server for providing the non-WAP terminal with Internet server data according to the common circuit data, an Internet service provider (ISP) having a public switched telephone network (PSTN) circuit layer, for transferring the common circuit data received through a PSTN from the non-WAP terminal to the Internet server, an interworking function (IWF) unit having a CSD protocol layer connected to the CSD protocol layers of each WAP terminal, and a TCP layer and an IP layer which are connected to the TCP and IP layers of each WAP server, for data communications between each WAP terminal and each WAP server, the method comprising the steps of: (a) determining whether data input to the IWF unit is WAP data or the common circuit data; (b) transferring the WAP data through the Internet to the corresponding WAP server if the input data is determined to be the WAP data in the step (a) and transferring the common circuit data through the ISP to the Internet server if the input data is determined to be the common circuit data in the step (b); (c) determining whether the data input to the IWF unit is WAP server data or the Internet server data; and (d) transferring the WAP server data through the Internet to the corresponding WAP terminal if the input data is determined to be the WAP server data in the step (c), and transferring the Internet server data through the PSTN to the non-WAP terminal if the input data is determined to be the Internet server data in the step (c), wherein each WAP terminal communicates with the IWF unit through a single Internet Protocol/Peer-to-Peer Protocol (IP/PPP) layer included in its own CSD protocol layer.